If you're not doing quests (aka, you can gain exp better elsewhere) what's the point in even adding/doing quests?
You get the xp from killing the mobs (if its mob based) and then the small extra xp reward. The quests are normally aimed at the mobs you'd be killing at the level you'd be when you picked up the quest, so really, you'd somewhat be leveling in that area anyway surely? So the extra xp at the end is just a bonus?
Level 11 - Killing omas to level
Quest is to kill 100 omas, so since you'd be leveling in omas anyway, you might aswell do the quest, get the same XP but the bonus XP at the end.
Obviously, if you're level 40 and you pick up a oma quest, then it would be pointless, none the less i do agree they do need upping abit from what i've seen.
I do quests because half the time i can't bare grinding, and it's just something slightly less boring :P